Wow, this thread is 3 years old... Think it was just before I started messing around with AVR microcontrollers. I did an LED candle with a Attiny13, using 5 LEDs (3 Amber, 2 Yellow). Thought the red was a little out of place. Never tried it in a pumpkin, but its plenty bright. Found a pretty cool flicker method using Bascom BASIC, I just pick a pin at random, and toggle it, and small delay before picking another pin. Haven't noticed any periods of all pins off (dark). I'm also a little abusive, don't use any resistors on the LEDs, 4 AA batteries for the supply, no regulator. I mostly use NiMh batteries, but works fine off disposables (6 volts, fresh). The Tiny13 data sheet recommends 5.5 volts max.